urequests: fix empty body response with some formatings

[jesuslg123]

Some engines generate responses with break lines using only \n instead of \r\n, so in order to support that kind of request response body format I have also added this check. Without the fix the body response comes empty as it does not stop on the if and empty the buffer with readline()

[andrewleech]

I'm not too sure about this, the http RFC appears to be pretty clear that \r\n is expected: https://stackoverflow.com/questions/5757290/http-header-line-break-style

I'd certainly prefer that the server gets fixed rather than patching a workaround here - do you know if this kind of issue is common?

[jesuslg123]

Hi @andrewleech ,

I agree, It is a pain to need manually replace the library as the server implementation won't be updated but I have to agree with you that the implementation should follow the specs.

I will close the PR.